refactor: modernise RPM builder with Python tooling v2

- Migrate from legacy shell-based build system to modern Python tooling
- Update all metadata.yaml files to new schema with per-distro builds
- Standardise build scripts with curl -L, envsubst, and error handling
- Convert nfpm.yaml templates to use environment variable substitution
- Update Dockerfile to accept all package metadata as build arguments
- Modernise Makefile to use new Python build tool commands
- Update CI workflow to use tools/build instead of make

rpms/unkin-undionly-kpxe/metadata.yaml

@@ -1,8 +1,18 @@
+---
+arch: amd64
+builds:
+  - image: git.unkin.net/unkin/almalinux8-rpmbuilder:latest
+    release: '1'
+    repository: [almalinux/el8]
+    version: 20250712.0.2
+  - image: git.unkin.net/unkin/almalinux9-rpmbuilder:latest
+    release: '1'
+    repository: [almalinux/el9]
+    version: 20250712.0.2
+description: iPXE network bootloader
+github: ipxe/ipxe
+homepage: https://github.com/ipxe/ipxe
+license: GPL-2.0 license
+maintainer: iPXE
 name: unkin-undionly-kpxe
-release: 1
-version: 20250712.0.2
-build:
-- distro: el/8
-  image: git.unkin.net/unkin/almalinux8-rpmbuilder:latest
-- distro: el/9
-  image: git.unkin.net/unkin/almalinux9-rpmbuilder:latest
+platform: linux

rpms/unkin-undionly-kpxe/resources/build.sh

@@ -1,4 +1,6 @@
 #!/usr/bin/bash
+set -e
+
 # clone the repo
 git clone https://github.com/ipxe/ipxe.git
 
@@ -16,5 +18,8 @@ make bin-x86_64-efi/ipxe.efi EMBED=main.ipxe
 cp bin/undionly.kpxe /app/
 cp bin-x86_64-efi/ipxe.efi /app/
 
+# Process nfpm.yaml with envsubst
+envsubst < /app/resources/nfpm.yaml > /app/nfpm.yaml
+
 # build rpm
-nfpm pkg --config /app/resources/nfpm.yaml --target /app/dist --packager rpm
+nfpm pkg --config /app/nfpm.yaml --target /app/dist --packager rpm

rpms/unkin-undionly-kpxe/resources/nfpm.yaml

@@ -1,16 +1,16 @@
 # nfpm.yaml
 
-name: unkin-undionly-kpxe
+name: ${PACKAGE_NAME}
 version: ${PACKAGE_VERSION}
 release: ${PACKAGE_RELEASE}
-arch: amd64
-platform: linux
+arch: ${PACKAGE_ARCH}
+platform: ${PACKAGE_PLATFORM}
 section: default
 priority: extra
-description: "iPXE network bootloader"
-maintainer: iPXE
-homepage: https://github.com/ipxe/ipxe
-license: GPL-2.0 license
+description: "${PACKAGE_DESCRIPTION}"
+maintainer: ${PACKAGE_MAINTAINER}
+homepage: ${PACKAGE_HOMEPAGE}
+license: ${PACKAGE_LICENSE}
 
 disable_globbing: false